Brushless direct current motors, also known as BLDC motors, are widely used in heating, ventilating and air-conditioning systems, also known as HVAC systems. For example, a BLDC motor is used to control a valve to regulate the amount of air flow. A traditional BLDC motor comprises a rotatable shaft which is supported by two separate bushings. The term “bushing”, as used in this specification, including the appended clams, refers to a self-lubricating sleeve bearing, especially an oil-impregnated sintered bronze sleeve bearing. However, the lubrication contained in the bushing is limited and is used up over time. In addition, moisture or dust in the air may permeate inside the bushing through the gap between the shaft and the bushing so that the bushing and shaft are easily damaged. Therefore, the life span of the BLDC motor and HVAC system are decreased.
Therefore, there is a desire for an improved BLDC motor for a HVAC system.